codeblocks-ep/help/html/programmerHelp/make/Commands-Search.html at master · maifeeulasad/codeblocks-ep · GitHub

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<title>GNU `make'</title>
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Node:<a name="Commands%2fSearch">Commands/Search</a>,
Next:<a rel="next" accesskey="n" href="Implicit-Search.html#Implicit%2fSearch">Implicit/Search</a>,
Previous:<a rel="previous" accesskey="p" href="Search-Algorithm.html#Search%20Algorithm">Search Algorithm</a>,
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<h4 class="subsection">Writing Shell Commands with Directory Search</h4>

   <p>When a prerequisite is found in another directory through directory search,
this cannot change the commands of the rule; they will execute as written.
Therefore, you must write the commands with care so that they will look for
the prerequisite in the directory where <code>make</code> finds it.

   <p>This is done with the <dfn>automatic variables</dfn> such as <code>$^</code>
(see <a href="Automatic.html#Automatic">Automatic Variables</a>).
For instance, the value of <code>$^</code> is a
list of all the prerequisites of the rule, including the names of
the directories in which they were found, and the value of
<code>$@</code> is the target.  Thus:

<pre class="example">     foo.o : foo.c
             cc -c $(CFLAGS) $^ -o $@
     </pre>

<p>(The variable <code>CFLAGS</code> exists so you can specify flags for C
compilation by implicit rules; we use it here for consistency so it will
affect all C compilations uniformly;
see <a href="Implicit-Variables.html#Implicit%20Variables">Variables Used by Implicit Rules</a>.)

   <p>Often the prerequisites include header files as well, which you do not
want to mention in the commands.  The automatic variable <code>$&lt;</code> is
just the first prerequisite:

<pre class="example">     VPATH = src:../headers
     foo.o : foo.c defs.h hack.h
             cc -c $(CFLAGS) $&lt; -o $@
     </pre>

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